docs: Improve main README.md and highlight community

Author: alamb

README.md

@@ -19,7 +19,9 @@
 
 # Native Rust implementation of Apache Arrow and Apache Parquet
 
-Welcome to the [Rust][rust] implementation of [Apache Arrow], the popular in-memory columnar format.
+Welcome to the [Rust][rust] implementation of [Apache Arrow], the popular
+in-memory columnar format and [Apache Parquet], the popularcolumnar analytics
+format. To join the community, see the [Community](#community) section below.
 
 This repository contains the following crates:
 
@@ -49,7 +51,7 @@ Versioning].
 
 Due to available maintainer and testing bandwidth, [`arrow`] crates ([`arrow`],
 [`arrow-flight`], etc.) are released on the same schedule with the same versions
-as the [`parquet`] and [`parquet-derive`] crates.
+as the [`parquet`] and [`parquet_derive`] crates.
 
 This crate releases every month. We release new major versions (with potentially
 breaking API changes) at most once a quarter, and release incremental minor
@@ -81,7 +83,7 @@ Planned Release Schedule
 
 ### Rust Version Compatibility Policy
 
-arrow-rs and parquet are built and tested with stable Rust, and will keep a rolling MSRV (minimum supported Rust version) that can only be updated in major releases on a need by basis (e.g. project dependencies bump their MSRV or a particular Rust feature is useful for us etc.). The new MSRV if selected will be at least 6 months old. The minor releases are guaranteed to have the same MSRV.
+arrow-rs and parquet are built and tested with stable Rust, and will keep a rolling MSRV (minimum supported Rust version) that can only be updated in major releases on an as needed basis (e.g. project dependencies bump their MSRV or a particular Rust feature is useful for us etc.). The new MSRV if selected will be at least 6 months old. The minor releases are guaranteed to have the same MSRV.
 
 Note: If a Rust hotfix is released for the current MSRV, the MSRV will be updated to the specific minor version that includes all applicable hotfixes preceding other policies.
 
@@ -152,7 +154,7 @@ including `join`s and window functions.
 
 You can find more details about each crate in their respective READMEs.
 
-## Arrow Rust Community
+## Community
 
 The `dev@arrow.apache.org` mailing list serves as the core communication channel for the Arrow community. Instructions for signing up and links to the archives can be found on the [Arrow Community](https://arrow.apache.org/community/) page. All major announcements and communications happen there.